Pulse width modulation (PWM) technology is a very effective technology by applying digital output of a microprocessor to control an analog circuit. It is widely applied in many fields such as measurement, communication, power control and transformation.
In short, PWM is a method to encode an analog signal level digitally. By the application of a high resolution counter the duty cycle of a square wave is modulated to encode a specific analog signal level. PWM signal remains to be digital since at any specific moment the direct current supply with full value is either ON or OFF. The voltage or current supply is applied on an analog load by a repetitive pulse sequence of ON or OFF. The direct current supply is applied on the load when it is ON and disconnected with the power supply when it is OFF. If the band width is large enough, any analog value can be encoded by PWM.
Particularly in the application of switching direct voltage circuit, the magnitude and variation extent of the output voltage is controlled by modulating the duty cycle of the pulse width modulation signal.
However, in the most of PWM switching direct voltage circuit applied by power supply the corresponding values of the output voltage and the duty cycle of PWM switching direct voltage circuit are generally in nonlinear state. Under such a state, the work efficiency of PWM is lowered.
Consequently, how to solve above mentioned conventional problems and shortcomings has been an objective of the present invention and manufacturers in the industry.